1. Field of the Invention
This invention relates to a collector for absorbing heat from incident solar energy and removing the absorbed heat by a heat transfer liquid, and particularly to a design and method of fabrication of a linear solar collector which substantially reduces the cost of manufacturing such units.
2. Summary of the Prior Art
Literally hundreds of patents have been issued on apparatus for collecting and transferring solar heat energy. In the common forms of such apparatus, the solar energy is incident on and absorbed by a metallic plate having a so-called "black body" coating thereon which effectively converts it to a black body type heat radiator. This black body surface is encased within a glazing of a transparent ceramic or plastic material and the inner surface of such glazing permits the transfer of light therethrough, but reflects back towards the heat absorbing black body plate substantially all infrared radiation emitted by the black body plate. Thus, the heat energy of the incident sunlight is trapped between the glazing and the heat absorbing black body plate. The heat developed in the black body plate is then transferred to a fluid which is generally conducted through metallic tubes or pipes lying in adjacent relationship to the black body heat absorbing plate. A layer of insulation is provided surrounding the lower surface of the black body plate and the pipes to prevent loss of heat in that direction.
Examples of common solar collectors are REDMOND, U.S. Pat. No. 4,255,213; HARDER, U.S. Pat. No. 4,338,921; FRIES, U.S. Pat. No. 4,325,359; GOOLSBY, U.S. Pat. No. 4,178,909; and HEYMAN, U.S. Pat. No. 4,172,311.
In each of the prior art patents, the need for an economical, yet efficient heat transfer solar collector is emphasized, but in every case, the prior art designs end up utilizing complicated shapes of plastic and/or metal for defining the heat absorbing clement and the conduits for transmitting a heat transfer fluid in intimate relationship with the heat absorbing element. If a substantially wider or larger unit is desired for a particular installation, the solution was to hook up a plurality of small units by complicated plumbing connections or to custom design and manufacture a larger unit of the desired dimensions. Either way, the total cost was excessive. The prior art clearly indicates the need for a modular design of solar heat collector wherein a plurality of identical modules may be readily assembled to provide a large collector of any desired width or length, for use on large school, office, and similar buildings for the heating of the entire building or a large quantity of hot water, which may be readily fabricated without involving the use of a plurality of separate self contained heat absorbing modules interconnected by complex heat transfer fluid conduits, or having separate conduits leading to the source of heat transfer fluid and to the heat storage or utilization apparatus.